Aerosol generating means for inhalation therapy devices

ABSTRACT

The invention describes an aerosol generator for inhalation therapy devices, in which an oscillatable assembly, consisting of at least a membrane and an oscillation generator, is mounted in an encapsulating means such that at least the membrane is exposed for the supply of liquid and the generation of an aerosol, whereas the remaining parts of the oscillatable assembly are protected. Mounting occurs by means of a flexible passage such that the oscillatory motions of the oscillatable assembly are not negatively affected.

The present invention relates to an aerosol generating means forinhalation therapy devices.

Different aerosol generators are known for use in inhalation therapydevices, the object of which is to generate an aerosol from a liquid.Particularly effective aerosol generators have a membrane which iscaused to oscillate by an oscillation generator in order to nebulise asupplied liquid. The oscillatable assembly of these aerosol generatorsis decisive for the quality of the generated aerosol and thus for dosageaccuracy, however, it is at the same time also generally very sensitive.In view of the therapeutic nature of the use in inhalation therapydevices, it is, however, necessary for the aerosol generator of aninhalation therapy device to be cleaned thoroughly on a regular basis.In order to do so, the aerosol generator generally has to be removedfrom the inhalation therapy device and cleaned, in certain cases alsoautoclaved, and thus the aerosol generator is often handled by thepatient/doctor.

Although the structure of the oscillatable assembly of an aerosolgenerator of the type discussed here is basically known, for example,from EP 0 615 470 A, there are no convincing suggestions as to howprotection of the oscillatable assembly and the handleability of theaerosol generator can be improved without negatively affecting theoscillatory motions of the oscillatable assembly during aerosolgeneration and consequently also the quality of the aerosol and thedosage accuracy.

According to the invention, this object is achieved by means of anaerosol generating means for inhalation therapy devices, comprising anoscillatable assembly having a membrane to which a liquid can besupplied for generation of an aerosol and an oscillation generatingmeans which causes the membrane to oscillate for generation of anaerosol, and comprising an encapsulating means for accommodating andmounting the oscillatable assembly such that parts of the oscillatableassembly are disposed in the interior of the encapsulating means and atleast the membrane is exposed for supply of a liquid and generation ofan aerosol, said encapsulating means having a flexible passage whichcontacts the oscillatable assembly.

A secure mounting of the oscillatable assembly as well as extensiveprotection against impurities and damage is achieved by the designaccording to the invention. The encapsulating means accommodates largeparts of the oscillatable assembly in its interior and only leaves thoseregions exposed which absolutely have to be freely accessible for supplyof the liquid and generation of the aerosol. Since the required passageof the encapsulating means is designed in a flexible manner according tothe invention, the oscillatory motions of the oscillatable assembly arenot negatively affected as a result of the mounting effected by means ofthe passage and the associated contact between the oscillatable assemblyand the encapsulating means. The encapsulating means is optimallydesigned such that the passage touches the oscillatable assembly in theregion of an oscillation nodal line.

The invention is explained in more detail below by means of embodimentsand referring to the figures.

FIG. 1 shows a sectional perspective view of a first embodiment of anaerosol generating means according to the invention,

FIG. 2 shows a sectional view of a second embodiment of an aerosolgenerating means according to the invention,

FIG. 3 shows a sectional view of a third embodiment of an aerosolgenerating means according to the invention,

FIG. 4 shows a sectional view of the arrangement of an aerosolgenerating means according to the invention in an example inhalationtherapy device, and

FIG. 5 shows a sectional view of a representation of oscillation statesin an aerosol generating means according to the invention.

FIG. 1 shows a sectional perspective view of a first embodiment of anaerosol generating means 1 according to the invention. This embodimentcomprises an oscillatable assembly having a membrane 2, an oscillationgenerator 3 and a substrate 4 to which the membrane 2 and theoscillation generator 3 are attached. However, in alternative designs,the oscillatable assembly can consist of just a membrane and anoscillation generator. It is characteristic of the oscillatable assemblyof an aerosol generator according to the invention that the oscillationgenerator 3 can be controlled by an activation signal such that itcauses the membrane 2 to oscillate so that a liquid present on a surfaceof the membrane is nebulised. A piezoelectric element, for example,comes into consideration as the oscillation generator 3, to which anelectric activation signal can be supplied to cause oscillation.

It is provided in the shown embodiment according to FIG. 1 that theliquid is supplied on the concave side of the membrane 2 and is releasedas an aerosol on the convex side of the membrane 2 when the membrane 2is caused to oscillate by the oscillation generating means 3. Bothsurfaces of the membrane 2 are exposed for this purpose, whereas othersections of the oscillatable assembly are disposed in the interior of anencapsulating means 5, which accommodates these areas of theoscillatable assembly. In the shown embodiment according to FIG. 1, theentire oscillation generator 3 and a large part of the substrate 4 aredisposed in the interior of the encapsulating means 5.

At the sites where the oscillatable assembly penetrates the wall of theencapsulating means 5 and the oscillatable assembly 2, 3 contacts theencapsulating means 5, the encapsulating means 5 comprises a flexiblepassage which, in the embodiment shown according to FIG. 1, has flexiblesealing lips 6 a and 6 b. Owing to the flexible sealing lips 6 a and 6b, which touch the oscillatable assembly, mounting of the oscillatableassembly is achieved on the one hand, and on the other it is achievedthat the interior of the encapsulating means 5 is closed, therebyprotecting the sections of the oscillatable assembly disposed in theinterior.

As can be seen from FIG. 1, the shape and size of the encapsulatingmeans 5 is adapted to the oscillatable assembly. In the shownembodiment, which comprises a circular membrane 2, an annularoscillation generator 3 and an annular substrate 4, this means that theencapsulating means 5 is also designed in an annular manner. Themembrane 2 is positioned in the opening of the annular encapsulatingmeans 5 and is accessible such that liquid can be supplied and aerosolcan be released.

An aerosol generator according to the invention can be handled as awhole with reduced risk for the oscillatable assembly since the partswhich do not have to be exposed for the supply of liquid and release ofaerosol are protected by the encapsulation. The encapsulated position oflarge parts of the oscillatable assembly has a particularly advantageouseffect when cleaning the aerosol generator. However, contamination ofthe encapsulated areas of the oscillatable assembly cannot occur eitherwhen used in an inhalation therapy device. Despite encapsulation, theareas of the oscillatable assembly disposed in the interior of theencapsulating means according to the invention can oscillate virtuallywithout being affected since the oscillatable assembly is only mountedat the flexible region 6 a, 6 b of the encapsulating means 5 and nofurther fixation of the oscillatable assembly, for example at the edge,is provided. In other words, the encapsulating means according to theinvention combines effective protection of the oscillatable assemblywith optimised mounting of the same.

In the embodiment shown in FIG. 1, the encapsulating means 5 comprises acasing 7, which is advantageously made of a comparatively hard material,for example a plastic, and flexible sealing lips 6 a and 6 b, which areattached to the casing 7 and form the flexible region of theencapsulating means 5. So that the oscillatable assembly can be insertedin the encapsulating means 5, the casing 7 of the embodiment accordingto FIG. 1 consists of two casing parts 7 a and 7 b, which are fittedtogether following insertion of the oscillatable assembly and arepermanently joined with one another at the joining point 7 c, forinstance by means of gluing.

FIG. 2 shows a second embodiment of an aerosol generating means 1according to the invention, which comprises an encapsulating means 5 aswell as an oscillatable assembly. In the embodiment shown in FIG. 2, theoscillatable assembly comprises a membrane 2 and an oscillationgenerator 3, which is attached to the membrane 2. Parts of the membrane2 and the oscillation generator 3 are positioned in an opening of theencapsulating means and are thus exposed so that a liquid can besupplied to the membrane 2 and an aerosol can be released. The remainingareas of the oscillatable assembly, in this embodiment the membrane 2and the oscillation generator 3, are disposed in the interior of theencapsulating means 5, with the edge of the oscillatable assembly beingable to oscillate in the interior of the encapsulating means 5 withoutbeing negatively affected, when, by activating the oscillation generator3, the membrane 2 is caused to oscillate so as to generate an aerosol.

According to the invention, the encapsulating means 5 of the secondembodiment comprises a passage 6 for passage of the oscillatableassembly through the wall of the encapsulating means 5. The passage 6 inthe embodiment shown in FIG. 2 is realised in the form of flexiblesealing lips 6 a and 6 b. The flexible sealing lips 6 a and 6 b lie onthe membrane 2 and the oscillation generator 3 respectively, whereby theoscillatable assembly is supported by the flexible passage 6, i.e. bythe flexible sealing lips 6 a and 6 b, of the encapsulating means 5.Owing to direct contact with the membrane 2 and the oscillationgenerator 3, the flexible sealing lips 6 a and 6 b at the same timeensure that the encapsulating means 5 is closed and that no substancescan penetrate into the interior of the encapsulating means 5.

Contrary to the first embodiment according to FIG. 1, the flexiblepassage 6, i.e. the flexible sealing lips 6 a and 6 b, is configuredintegrally with the casing 7 of the encapsulating means 5 in theembodiment shown in FIG. 2. As is shown in FIG. 2, the sufficientflexibility of the flexible passage 6 is realised in this embodiment inthat the wall thickness of the encapsulating means 5 is designed to beso thin in the region of the passage 6 that a flexible region isrealised, which furthermore preferably has the form of curved sealinglips. In the remaining area of the casing 7, the encapsulating meansotherwise advantageously has a wall thickness which provides sufficientstability to protect the parts of the oscillatable assembly positionedin the interior of the encapsulating means 5. The material from whichthe encapsulating means 5 according to the second embodiment as shown inFIG. 2 is made is preferably a plastic, a rubber or silicone. With thesematerials, the encapsulating means 5 can be configured in one piecesince the elasticity of the material provides the entire structure witha sufficient amount of flexibility and elasticity, which enables theoscillatable assembly to be inserted in the passage 6, i.e. between thesealing lips 6 a and 6 b. If sufficient elasticity is not realizable,the casing 7 of the encapsulating means 5 according to the secondembodiment can also be configured in two parts, as was described inconnection with the first embodiment.

It is furthermore shown in FIG. 2 of the second embodiment of theinvention, how electric supply leads 9 a and 9 b can be guided throughopenings 8 a and 8 b into the interior of the encapsulating means 5 inorder to enable the supply of an activation signal to the oscillationgenerator 3.

FIG. 3 shows an alternative embodiment as regards the contacting of theoscillatable assembly. Reference is otherwise made to the description ofthe second embodiment. In the third embodiment of the inventionaccording to FIG. 3, contacting of the oscillatable assembly occurs bymeans of contact springs 10 a and 10 b, which contact the oscillatableassembly. In the embodiment shown in FIG. 3, the first contact spring 10a contacts the membrane 2 and the second contact spring 10 b contactsthe oscillation generator 3. Since the membrane of an aerosol generatorin question here is generally produced from a conductive material, anactivation signal supplied via the contact spring 10 a is relayed to theoscillation generator 3, for example a piezoelectric element. If asubstrate is present, as is described in connection with the firstembodiment, one of the contact springs can also be arranged such that itcontacts the substrate which is generally also produced from aconductive material. If the membrane and/or substrate are not made froma conductive material, a connection can be established between thecontact spring and the oscillation generator by means ofthrough-connections through the membrane/substrate or by conductivecoatings on the surface thereof.

The first and second contact springs 10 a and 10 b are mounted on thecasing 7 of the encapsulating means 5, preferably throughthrough-connections 11 a and 11 b which, in addition to mounting thecontact springs 10 a and 10 b, also form the contact points for thecontact springs that are accessible from the outside. An easilydetachable electrical connection to control circuits accommodated in theinhalation therapy device can thereby be established in a simple mannerwhen an aerosol generator according to the invention is inserted in aninhalation therapy device. Contact springs are advantageous with regardto production of the aerosol generator according to the invention sincesimple contacting when inserting the oscillatable assembly, inparticular when inserting it into a two-part casing, is therebypossible.

FIG. 4 helps to explain the use of an aerosol generating means 1according to the invention in a schematically shown inhalation therapydevice 100, using as an example the design of the second and thirdembodiments, however without electric supply leads. The inhalationtherapy device 100 comprises a first casing part 101, which accommodatesa nebulising chamber 102 in its interior and comprises a mouthpiece 103,via which the patient inhales an aerosol generated into the nebulisingchamber 102. The inhalation therapy device furthermore comprises aliquid container 104, in which a liquid 105 can be stored. The liquid105 filled in the liquid reservoir 104 is disposed on one side of themembrane of the aerosol generator 1 according to the invention. When themembrane is caused to oscillate, an aerosol 106 is generated from theliquid 105, which enters the nebulising chamber 102 of the inhalationtherapy device 100.

As is shown in FIG. 4, the inhalation therapy device 100 shown as anexample can be separated into two casing parts 101 and 104 at aseparation point 107. A first receptacle 108, which is configuredintegrally with the first casing part 101, and a second receptacle 109,which is configured integrally with the second casing part 104 of theinhalation therapy device 100, is disposed in this region. An aerosolgenerator 1 according to the invention is inserted into the receptacles108 and 109 and the two parts of the casing are then connected together.The inhalation therapy device is then ready for use.

FIG. 5 shows an aerosol generating means 1 according to the inventionhaving an encapsulating means 5 and an oscillatable assembly 2, 3. Asregards the details hereof, reference is made to the detailedexplanation of the three embodiments described above. The point at whichthe flexible passage 6 of the encapsulating means 5 advantageouslycontacts the oscillatable assembly is to be explained by means of FIG.5. For this purpose, the position of the oscillatable assembly in itsidle state is indicated in FIG. 5 by the dashed lined A, whereas thedashed line B indicates a deflected position of the oscillatableassembly. As is apparent from FIG. 5, the contact point of the sealinglips 6 a and 6 b of the encapsulating means 5 is in the region of anoscillation node or an oscillation nodal line. Owing to thisadvantageous arrangement of the contact point between the oscillatableassembly and the encapsulating means, the oscillation behaviour of theoscillatable assembly is virtually unaffected by the encapsulating means5 since the contact with and mounting of the oscillatable assembly bythe encapsulating means takes place at a point at which there is almostno movement.

The position of the oscillation nodal lines is dependent on thefrequency of the activation signal and the structure of the oscillatableassembly. However, the encapsulating means 5 can in any case be designedsuch that the flexible region 6 of the encapsulating means 5 contactsand mounts the oscillatable assembly at an oscillation nodal line.

It must be noted with regard to FIG. 5 that the deflection of line B hasbeen shown much larger than actually occurs for the purpose ofclarification. Furthermore, it is obvious that several antinodes canalso occur between the contact points if the oscillatable assembly iscorrespondingly activated.

The positioning of the contact points between the oscillatable assemblyand the encapsulating means along an oscillation nodal line of theoscillatable assembly is a particularly advantageous design of theaerosol generating means according to the invention. If contact with andmounting of the oscillatable assembly occurs in this manner, optimalmounting is also ensured in addition to the encapsulating effectsdescribed above since the oscillating structure, namely the oscillatableassembly consisting of the membrane and oscillation generator andpossibly a substrate, can oscillate virtually without being affected.This is because, on the one hand, oscillation of the oscillatableassembly is not affected as a result of mounting by the flexible region6 of the encapsulating means 5. On the other hand, there is no borderingat the edge of the oscillatable assembly which can lead to a negativeeffect. Protection of at least parts of the oscillatable assembly, forexample the contacting, is in any case always achieved by theencapsulating means, and thus an aerosol generating means having anoptimally oscillating membrane and which is on the whole easy to handleis realised.

1. An aerosol generating means for inhalation therapy devices, comprising: an oscillatable assembly having a membrane, to which a liquid can be supplied for generation of an aerosol, and an oscillation generating means, by means of which the membrane can be caused to oscillate for generation of an aerosol; an encapsulating means for accommodating and mounting the oscillatable assembly, the encapsulating means defining an interior such that at least part of the membrane and at least part of the oscillation generating means are disposed in the interior of the encapsulating means and at least another part of the membrane is exposed for supply of a liquid and generation of an aerosol, said encapsulating means having a passage, wherein the passage of the encapsulating means comprises at least two sealing lips, which contact the oscillatable assembly, wherein the encapsulating means comprises a casing and the at least two sealing lips, wherein the parts of membrane and the oscillation generating means disposed in the interior of the encapsulating means are protected by the encapsulating means against exposure to the liquid and the generated aerosol, and wherein the casing and the at least two sealing lips are formed integrally; and a housing having a receptacle configured to receive and mount the encapsulating means.
 2. An aerosol generating means according to claim 1, wherein the passage of the encapsulating means contacts the oscillatable assembly in the region of an oscillation nodal line.
 3. An aerosol generating means according to claim 1, wherein the passage is attached to the casing.
 4. An aerosol generating means according to claim 1, wherein the casing is formed in two parts.
 5. An aerosol generating means according to claim 1, wherein the encapsulating means comprises openings for electric supply leads.
 6. An aerosol generating means according to claim 5, wherein the encapsulating means comprises electric supply leads and/or electric contact springs in its interior for supplying electric activation signals to the oscillatable assembly.
 7. An aerosol generating means according to claim 6, wherein the supply leads are guided through the openings.
 8. An aerosol generating means according to claim 6, wherein the electric contact springs are mounted by means of through-connections, which are disposed in the openings and form contact points on the outer surface of the encapsulating means.
 9. An aerosol generator for inhalation therapy devices, comprising: an oscillatable assembly having a membrane, to which a liquid can be supplied for generation of an aerosol, and an oscillation generator, by which the membrane can be caused to oscillate for generation of an aerosol; a casing for accommodating and mounting the oscillatable assembly, the casing defining an interior such that at least part of the membrane and at least part of the oscillation generator are disposed in the interior of the casing and at least another part of the membrane is exposed for supply of a liquid and generation of an aerosol, said casing having a flexible passage, wherein the flexible passage of the casing comprises at least two flexible sealing lips, which contact the oscillatable assembly, wherein the parts of the membrane and the oscillation generator disposed in the interior of the casing are protected by the casing against exposure to the liquid and the generated aerosol, and wherein the flexible sealing lips and the casing are formed integrally of a flexible material; and a housing having a receptacle configured to receive and mount the casing. 